import express, { Request, Response } from "express";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import { createServer } from "./server.js";
export interface McpServerEndpoint {
url: string;
port: number;
}
export async function startStreamableHttpMcpServer(port?: number): Promise<McpServerEndpoint> {
const app = express();
app.use(express.json());
const server: McpServer = createServer();
const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({
sessionIdGenerator: undefined, // set to undefined for stateless servers
});
// Setup routes for the server
await server.connect(transport);
app.post('/mcp', async (req: Request, res: Response) => {
console.log('Received MCP request:', req.body);
try {
await transport.handleRequest(req, res, req.body);
} catch (error) {
console.error('Error handling MCP request:', error);
if (!res.headersSent) {
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: 'Internal server error',
},
id: null,
});
}
}
});
app.get('/mcp', async (req: Request, res: Response) => {
console.log('Received GET MCP request');
res.writeHead(405).end(JSON.stringify({
jsonrpc: "2.0",
error: {
code: -32000,
message: "Method not allowed."
},
id: null
}));
});
app.delete('/mcp', async (req: Request, res: Response) => {
console.log('Received DELETE MCP request');
res.writeHead(405).end(JSON.stringify({
jsonrpc: "2.0",
error: {
code: -32000,
message: "Method not allowed."
},
id: null
}));
});
// Start the server
const PORT = Number(port || process.env.PORT || 3088);
return new Promise((resolve, reject) => {
const appServer = app.listen(PORT, (error) => {
if (error) {
console.error('Failed to start server:', error);
reject(error);
return;
}
const endpoint: McpServerEndpoint = {
url: `http://localhost:${PORT}/mcp`,
port: PORT
};
console.log(`Code Runner Streamable HTTP MCP Server listening at ${endpoint.url}`);
resolve(endpoint);
});
// Handle server errors
appServer.on('error', (error) => {
console.error('Server error:', error);
reject(error);
});
});
}